High frequency package, wiring board, and high frequency module

ABSTRACT

A high frequency package is arranged such that it comprises a dielectric substrate provided with an input terminal and an output terminal, a high frequency element mounted on the surface of the dielectric substrate, and a high frequency line formed on the dielectric substrate for connecting the high frequency element with the input terminal and with the output terminal, wherein a transmission characteristic from the input terminal to the output terminal has the property of cyclically varying in relation to frequency. The length of the high frequency line is regulated such that the frequency of signals transmitted along the high frequency line is located at a part of the cyclic variation curve of the transmission characteristic where transmittance is large. By arranging the structure in such a manner, loss of high frequency signals having frequencies of 10 GHz or more can be reduced.

[0001] This application is based on application No. 2000-160750 filed inJapan, the content of which is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a high frequency package, awiring board and a high frequency module, in which high frequencyelements are loaded and high frequency signals having frequencies of 10GHz or more are transmitted.

[0004] 2. Description of the Related Art

[0005] In the recent highly information-driven society, utilization ofradio waves for information transmission has been under study in whichradio waves ranging from microwaves whose frequency range is 1-30 GHz tomillimeter waves whose frequency range is 30-300 GHz are dealt with.Application systems using millimeter waves, for example, vehicleinterval radars have been proposed.

[0006] As a structure of high frequency module adopted in such systems,the structure of a known multichip high frequency package, in which aplurality of high frequency elements are mounted on one substrate andhermetically sealed altogether by a case, is the mainstream.

[0007] A schematic sectional view of this known multichip high frequencypackage is shown in FIG. 5. A multichip high frequency package 31comprises a dielectric substrate 32, a frame 33, a cap 34, and aplurality of high frequency elements 35 sealed within the package. Eachof the high frequency elements 35 is connected with a high frequencyline 36 formed on the surface of the dielectric substrate 32 by a wirebonding 37.

[0008] Such a multichip high frequency package needs to have a largesize for arranging the necessary high frequency circuit within thepackage. As a result, this has a problem in the yield of hermeticsealing caused by camber of the substrate, deformation of the frame andthe cap or the like.

[0009] In order to solve this problem, another kind of high frequencymodule has been considered. In this module, each high frequency elementis separately packaged, hermetically sealed and mounted on a substrateso that the individual high frequency packages are connected with oneanother by a high frequency line on the wiring board.

[0010] However, in the case of such a high frequency module having highfrequency packages each of which includes a high frequency elementseparately and is mounted on the wiring board, when the signal frequencyis as high as 10 GHz or more, reflection of the high frequency signalsbecomes great in areas where the high frequency packages are connectedwith the wiring board. Loss in such areas is so great that it is hard toobtain the required performance, which makes it very difficult to puthigh frequency modules in such a mode to practical use.

[0011] It is an object of the present invention to provide a highfrequency package loaded with high frequency elements, a wiring board onwhich the high frequency packages are mounted, and a high frequencymodule with the high frequency packages incorporated thereinto having astructure capable of reducing loss of high frequency signals especiallythose having frequencies of 10 GHz or more.

BRIEF DESCRIPTION OF THE INVENTION

[0012] After accumulating studies on the loss of signals in highfrequency modules having high frequency packages that are loaded withhigh frequency elements and mounted on a wiring board, the presentinventors focused on the fact that a transmission characteristic ofsignals transmitted from a terminal to the other terminal had theproperty of cyclically varying in relation to frequency, and have foundout that loss of high frequency signals could be reduced by regulatingthe high frequency line between each set of terminals in the highfrequency package and the wiring board such that the frequency ofsignals transmitted along the high frequency line corresponds to thefrequency located at a peak part (where transmittance is large) of thecyclic variation curve of the transmission characteristic.

[0013] A high frequency package according to the present invention ischaracterized in that a transmission characteristic of signals (which isthe same as the insertion loss and corresponds to S21 in S parameter)transmitted from an input terminal to an output terminal has theproperty of cyclically varying in relation to frequency, and that thefrequency of signals transmitted along a high frequency line inside thehigh frequency package corresponds to that at a part of the cyclicvariation curve of the transmission characteristic where transmittanceis large (claim 1).

[0014] The wiring board according to the present invention is one thathas at least two high frequency packages mounted thereon, in which atransmission characteristic from one terminal portion to the otherterminal portion on a high frequency line connecting the two highfrequency packages has the property of cyclically varying in relation tofrequency, and the frequency of signals transmitted along the highfrequency line corresponds to that at a part of the cyclic variationcurve of the transmission characteristic where transmittance is large(claim 6).

[0015] In addition, according to the present invention, a high frequencymodule may be arranged such that the high frequency packages having thespecific structure above are mounted on a wiring board that comprises ahigh frequency line formed on the surface of a dielectric substrate(claim 10), and that at least two high frequency packages loaded withhigh frequency elements are mounted on the wiring board having thespecific structure above (claim 11).

[0016] Furthermore, the most desirable high frequency module accordingto the present invention is arranged such that the high frequencypackages having the specific structure above in which transmission lossis reduced are mounted on the wiring board having the specific structureabove in which transmission loss is reduced (claim 12).

[0017] Generally, in a high frequency module in which a high frequencypackage is mounted on a wiring board, when the frequency becomes as highas 10 GHz or more, signals reflect in areas where the high frequencypackage is connected with the wiring board causing the loss thereof tobe large. According to the present invention, however, the length of thehigh frequency line between the input terminal and the output terminalin the high frequency package and the length of the high frequency linebetween the high frequency packages connecting the high frequencypackages on the wiring board are regulated, and the cycle of thefrequency variation of the transmission characteristic in accordancewith each length is adjusted such that the signal frequency is locatedat a peak part of the cyclic variation curve of the transmissioncharacteristic, thereby reducing transmission loss in the high frequencypackage and the wiring board, and accordingly reducing transmission lossin the high frequency module comprising the high frequency packagesmounted on the wiring board.

[0018] The peak part of the cyclic variation curve should preferablysatisfy the following mathematical formula:

f ₁+{(f ₂ −f ₁)/4}≦f ₀ ≦f ₂−{(f ₂ −f ₁)/4}  [Formula 1]

[0019] wheref_(0 ‘represents the frequency of signals transmitted along the high frequency line, f)₁ represents the frequency on the cyclic variation curve of thetransmission characteristic at a part on the lower frequency sideadjacent to f₀, where transmittance is small, and f₂ represents thefrequency on the curve at a part on the higher frequency side adjacentto f₀, where transmittance is small.

[0020] Moreover, it is preferable for the length of the high frequencyline along which signals are transmitted to be (2n+1)λ/4 (n: an integralnumber, λ: wavelength of the signal frequency). This makes it possibleto suppress transmittance loss due to the connection.

[0021] As discussed so far, the high frequency package, the wiring boardand the high frequency module according to this invention are arrangedsuch that the length of the high frequency line between the inputterminal and the output terminal in the high frequency package and thelength of the high frequency line connecting two high frequency packageson the wiring board are regulated in accordance with the wavelength ofsignals to be transmitted, and the frequency of the signals to betransmitted is controlled so as to be located at a peak part of thecyclic variation curve of the transmission characteristic, therebybringing the reflection down to a minimum value and accordingly bringingthe loss down to a minimum value. Reduction of loss due to theconnection is therefore made possible, and a high frequency module thatcan deal with frequencies as high as 10 GHz or more can be realized in amode in which high frequency packages are mounted on a wiring board.

[0022] Specific structural details of the present invention arehereinafter described referring to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1A is a schematic plan view illustrating an embodiment of thehigh frequency module according to the present invention.

[0024]FIG. 1B is a schematic sectional view of the above embodiment

[0025]FIG. 2 is a graph showing a transmission characteristic forexplaining the principle of the present invention.

[0026]FIG. 3A is a schematic plan view of a high frequency package forevaluation in an example.

[0027]FIG. 3B is a schematic plan view of a wiring board.

[0028]FIG. 3C is a schematic sectional view of the high frequencypackage for evaluation mounted on the wiring board.

[0029]FIG. 4A is a graph showing a transmission characteristic of anassembled sample with high frequency package Al for evaluation in theexample.

[0030]FIG. 4B is a graph showing a transmission characteristic of anassembled sample with high frequency package A2 for evaluation.

[0031]FIG. 5 is a schematic sectional view illustrating the structure ofa known multichip high frequency module.

DETAILED DESCRIPTION OF THE INVENTION

[0032]FIG. 1A is a schematic plan view of a high frequency moduleaccording to this invention, and FIG. 1B is a schematic sectional viewof the same.

[0033] In this high frequency module, a high frequency line 2 forinputting high frequency signals connected to an outer antenna is formedon one end of a wiring board 1. In an end portion of this high frequencyline 2, a terminal portion 2 a to be connected with a high frequencypackage is formed.

[0034] A high frequency package 5 (switching device) having a firstswitching element 3 and a second switching element 4 hermetically sealedtherein is mounted on the wiring board 1. This high frequency package 5comprises a dielectric substrate 6, an input terminal 8 a and an outputterminal 8 b provided beneath the dielectric substrate 6.

[0035] These terminals 8 a and 8 b are connected by a high frequencyline 7 that is formed on the dielectric substrate 6. This high frequencyline comprises a microstrip line including a signal line 7 a and aground layer 7 b. Meanwhile, the signal line 7 a formed on the insidesurface of the dielectric substrate 6 being sealed in and the signalline 7 a formed on the rear surface of the dielectric substrate 6 areconnected by a through-hole conductor 9 penetrating the dielectricsubstrate 6, without electrically contacting with the ground layer 7 b.

[0036] The input terminal 8 a of this high frequency package 5 isconnected with the terminal portion 2 a on the wiring board 1 by meansof a conductive adhesive 10 such as solder. Also, the output terminal 8b of the high frequency package 5 is connected with a terminal portion11 a formed on one end of the high frequency line 11 formed on thewiring board 1 by means of the conductive adhesive 10.

[0037] In addition, a high frequency package 14 (down converter device)comprising a mixer element 12 and a high frequency oscillator 13hermetically sealed therein is connected with the other end part of thehigh frequency line 11 on the wiring board 1. This high frequencypackage 14 has a structure similar to that of the high frequency package5, and includes a dielectric substrate 15, an input terminal 16 a, anintermediate frequency terminal 16 b and a high frequency line 17comprising a microstrip line.

[0038] The input terminal 16 a of the high frequency package 14 isconnected with the terminal portion 11 b of the high frequency line 11by means of the conductive adhesive 10. Also, the intermediate frequencyterminal 16 b is connected with a terminal portion of an intermediatefrequency line 18 formed on the wiring board 1 by means of theconductive adhesive.

[0039] In such a high frequency module, high frequency signalsintroduced by the high frequency line 2 are screened by the switchingdevice comprising a high frequency package 5 within which the firstswitching element 3 and the second switching element 4 are hermeticallysealed. The input signals that have been screened by the switchingdevice are further transmitted through the high frequency line 11 to thedown converter device comprising the high frequency package 14 withinwhich the mixer element 12 and the high frequency oscillator 13 arehermetically sealed. The signals are converted by the down converterdevice into intermediate frequency signals having a frequency of 1 GHz,and outputted to the intermediate frequency line 18 on the wiring board1.

[0040] When a high frequency module has such a structure as above, in aseries of paths along which high frequency signals are transmitted,reflection of the signals is likely to occur in areas where each deviceis connected with the line 2, 11 or 18. This causes transmission loss ofthe high frequency signals to be great.

[0041] Also, in the case of transmitting high frequency signals along atransmission line such as a microstrip line in such a high frequencymodule, due to its high frequency, the transmission loss thereof islarge by nature. This has been a problem in assembling such a highfrequency module. Reflection of signals in the connection areas is notonly a problem of further increased loss. It also includes a problemthat the reflected signals can cause malfunction of the elements andoscillation of the circuit.

[0042] Reflection of high frequency signals is generated atdiscontinuous points of the transmission line, namely, connection pointsbetween the devices and lines 7, 11, and 18 on the wiring board 1. Thebehavior of the reflection changes depending on the length of the linebetween a discontinuous point and another discontinuous point.

[0043]FIG. 2 is a graph for explaining the principle of this invention,which shows each transmission characteristic when a high frequency lineis sandwiched between a discontinuous point and another discontinuouspoint, where the length of the high frequency line between the twodiscontinuous points is L1 or L2 (L1<L2). The vertical axis indicatestransmittance S21 (arbitral unit), and the horizontal axis indicatesfrequency (GHz).

[0044] As shown in FIG. 2, in either case, the transmissioncharacteristic of the high frequency line between two discontinuouspoints has the property of cyclically varying in relation to thefrequency.

[0045] The reflection of signals is small at parts (peaks) where thetransmittance is large, and is large at parts (troughs) where thetransmittance is small. According to the cyclic variation curve in FIG.2, when the signal frequency is 77 GHz (f₀), the curve is at a trough inthe case of the high frequency line length L1, where the loss is large.However, in the case of the high frequency line length L2 that is alittle longer than L1, the curve is at a peak, where the loss is small.

[0046] This invention is one that utilizes this transmissioncharacteristic of high frequency signals such that when there isdiscontinuity in a transmission line such as a connection point betweenthe line on the wiring board and a device, the length of thetransmission line between a discontinuous point and anotherdiscontinuous point is adjusted so as to reduce loss due to reflection.

[0047] In the present invention, the length of the transmission linebetween the discontinuous points is adjusted so that the frequency ofsignals transmitted along the transmission line is located at a peakpart of the cyclic variation curve of the transmission characteristic.

[0048] In the high frequency module discussed referring to FIGS. 1A, 1B,high frequency lines sandwiched between discontinuous points are asfollows:

[0049] 1) High frequency line 2 connecting an antenna and the highfrequency package 5 that functions as a switching device. 2) A group ofhigh frequency lines in the high frequency package 5 serving as aswitching device, which are included in the route from the inputterminal 8 via the high frequency line 7 and the elements 3, 4 to theoutput terminal 8 b

[0050] 3) High frequency line 11 from the terminal portion 11 a to theother terminal portion 11 b connecting two high frequency packages 5 and14 on the wiring board 1.

[0051] 4) A group of high frequency lines in the high frequency package14 that functions as a down converter device, which are included in theroute from the input terminal 16 a via the high frequency line 17 andthe elements 12, 13 to the intermediate frequency terminal 16 b.

[0052] In particular, the high frequency lines listed in 2) 4) and/or 3)greatly influence the loss of the high frequency module. It is thereforedesirable to control these lines so as to reduce transmittance loss.

[0053] More specifically, they should be controlled so as to satisfy thefollowing mathematical formula:

f ₁+{(f ₂ −f ₁)/4≦f ⁰ 23 f ₂−{(f ₂-f ₁)/4}  [Formula 1]

[0054] where f₀ represents the frequency of signals transmitted alongthe high frequency line, f₁ represents the frequency on the cyclicvariation curve of the transmission characteristic in each line at atrough part on the lower frequency side adjacent to f₀, and f₂represents the frequency on the curve at a trough part on the higherfrequency side adjacent to f₀.

[0055] This is a formula defining the peak part of the cyclic variationcurve, which means that one peak part is located within a frequencyrange of inner ½ of the frequency range between the trough partsadjacent to the peak part.

[0056] In order to make the transmission characteristic of a highfrequency line satisfy the specific relation described above, it isdesirable that the length L of each line is represented as:L=(2n+1) λ/4(n is an integral number, and λ is wavelength of the signal frequency).

[0057] In the present invention, as a high frequency package to beincorporated into a high frequency module, a high frequency package thatsatisfies the above stated relations is mounted on a wiring board sothat it is possible to reduce at least transmittance loss within thehigh frequency package in the high frequency module.

[0058] In addition, by mounting high frequency packages on a wiringboard that satisfies the above relations, transmittance loss can bereduced at least in the line between the high frequency packages on thewiring board.

[0059] Furthermore, by incorporating high frequency packages thatsatisfy the above relations into a wiring board that satisfies the aboverelations, transmittance loss within the high frequency packages as wellas that in the line between the high frequency packages on the wiringboard can be reduced so that the overall transmittance loss in the highfrequency module can be further decreased.

[0060] In addition, regulating the above described lines 3) and 4) so asto satisfy the above relations enables transmittance loss of the highfrequency module to decrease further.

EXAMPLE

[0061] A high frequency package A for evaluation was fabricated in orderto examine how lengths of a high frequency transmission line influencethe signal reflection. The pattern of the rear surface of the dielectricsubstrate of the frequency package A is shown in FIG. 3A, the pattern ofa wiring board B is shown in FIG. 3B, and a schematic sectional view ofthe high frequency package A for evaluation mounted on the wiring boardB is shown in FIG. 3C.

[0062] The high frequency package A for evaluation has a dielectricsubstrate 21 comprising alumina ceramics and having a signal conductor22 on its rear surface, and a ground layer 23 inside the substrate. Thesignal conductor 22 and the ground layer 23 constitute a microstrip line24. As shown in FIG. 3A, the end parts of the signal conductor 22 arenarrowed in the end portions of the dielectric substrate 21, and groundpatterns 25 electrically connected with the ground layer 23 are formedin both sides of the end parts of the signal conductor 22. The end partsof the signal conductor 22 and the ground patterns 25 form connectionterminals.

[0063] Similarly, the wiring board B has a dielectric substrate 26comprising alumina ceramics and having a signal conductor 27 on itsfront surface and a ground layer 28 inside as shown in FIG. 3B. Thesignal conductor 27 and the ground layer 28 constitute a microstrip line29.

[0064] The high frequency package A for evaluation is mounted on thesurfaces of the terminal portions of the microstrip line 29 on thewiring board B by means of solder 30 as shown in FIG. 3C.

[0065] A high frequency package Al having a distance between theconnection terminals Lp of 5.6 mm, and a high frequency package A2having a distance between the connection terminals Lp of 6.0 mm werefabricated for the high frequency package A for evaluation. Thesepackages were respectively mounted on the wiring board B, and highfrequency signals were transmitted. The influence of the connectionareas was evaluated.

[0066] The transmission characteristic (reflection characteristic,insertion loss) between the input terminal and the output terminal onthe wiring board B in the frequency range of 60-90 GHz was measured. Aresult of the measurement in the case of Lp=5.6 mm (=14×λ/4)is shown inFIG. 4A, and that in the case of Lp=6.0 mm (=15×λ/4)is shown in FIG. 4B.It is apparent that, in both cases, the transmission characteristic ofthe high frequency line cyclically varies in relation to the variationof the frequency.

[0067] When signals having a frequency of 76 GHz ( wavelength λ=1.49mm)were transmitted in both of the high frequency packages, the highfrequency package Al had a signal reflection (S11) of −10.0 dB, and aloss (S21) of −2.3 dB (FIG. 4A).

[0068] On the other hand, the high frequency package A2 had a signalreflection (S11) of −22.9 dB, and a loss (S21) of −1.6 dB (FIG. 4B).

[0069] When the high frequency package Al (FIG. 4A) is compared with thehigh frequency package A2 (FIG. 4B), the high frequency package Al haslarger signal reflection (S11), as well as larger loss (S21).

[0070] As the result above shows, when signals having a frequency of 76GHz are transmitted, transmission loss can be reduced by using the highfrequency package A2 in which the frequency of signals transmitted alongthe high frequency line is located at a peak part of the cyclicvariation curve of the transmission characteristic.

[0071] As is shown above, the cyclic variation of the transmissioncharacteristic in relation to the frequency corresponds to the distancebetween the connection terminals. When the length of the transmissionline between the connection areas is an integral multiple of one-halfthe wavelength of the signals, the reflection is a minimum value, andthe loss is also a minimum value accordingly.

[0072] The effective dielectric constant of the microstrip line of eachof the high frequency packages A1 and A2 is approximately 6. In eachcase of the high frequency packages A1 and A2 for evaluation, the lengthof the transmission line between the connection areas becomes anintegral multiple of one-half the wavelength of the signals at every10.1 GHz, 9.4 GHz, respectively, in calculation, which correspond to theabove measurement.

[0073] Therefore, when mounting a high frequency package, by adjustingthe length of the transmission line between the connection areas to anintegral multiple of one-half the wavelength of the signals, the packagehas a minimum reflection, having a minimum loss accordingly. This allowsfor reduction of loss due to the connection, thereby appropriatelyrealizing a high frequency module dealing with frequencies of 10 GHz ormore.

[0074] A surface-mounting type high frequency package in which solderingis employed was used as the high frequency package for evaluation inFIGS. 4A and 4B. However, the structure of the high frequency packageaccording to this invention is not limited to the above one, but may bearranged such that the connection terminals are connected with thewiring board by means of wire, which will have the same effect.

[0075] Based on the results described above, a high frequency module isarranged in the manner of FIGS. 1A-1C according to this invention, wherethe connection terminals 11 a and 11 b of the high frequency line 11connecting the high frequency packages 5 and 14 on the wiring board 1has an interval length Lb of, for example, 0.4 mm or 1.2 mm, which is(2n+1)λ/4 (n is an integral number). In this way, the frequency ofsignals transmitted along the high frequency line is located at a peakpart of the cyclic variation curve of the transmission characteristic sothat the reflection is at a minimum, and the loss is accordingly at aminimum, thereby reducing loss caused by the connection. As a result, itis possible to reduce loss of signals having frequencies of 10 GHz ormore in the high frequency line connecting the high frequency packagestogether on the wiring board.

[0076] In addition, by mounting such high frequency packages in whichthe lengths of the lines are adjusted on the wiring board in which thelength of the line is adjusted as above, this invention has made itpossible to provide a high frequency module with reduced transmittanceloss.

1. A high frequency package comprising: a dielectric substrate providedwith an input terminal and an output terminal; a high frequency elementmounted on the surface of the dielectric substrate; and a high frequencyline formed on the dielectric substrate for connecting the highfrequency element with the input terminal and with the output terminal;wherein a transmission characteristic from the input terminal to theoutput terminal has the property of cyclically varying in relation tofrequency, and the frequency of signals transmitted along the highfrequency line corresponds to that at a part of the cyclic variationcurve of the transmission characteristic where transmittance is large.2. The high frequency package according to claim 1, which satisfies: f₁+{(f ₂ −f ₁)/4}≦f ₀ ≦f ₂−(f₂ −f ₁)/4}  [Formula 1] where f₀ representsthe frequency of signals transmitted along the high frequency line, f₁represents the frequency on the cyclic variation curve of thetransmission characteristic at a part on the lower frequency sideadjacent to f₀, where transmittance is small, and f₂ represents thefrequency on the curve at a part on the higher frequency side adjacentto f₀, where transmittance is small.
 3. The high frequency packageaccording to claim 1, wherein the length of the high frequency line fromthe input terminal to the output terminal is (2n+1)λ/4 (n: an integralnumber, λ: wavelength of signal frequency)
 4. The high frequency packageaccording to claim 1, wherein the high frequency element serves as aswitching device.
 5. A wiring board for mounting at least two highfrequency packages thereon, wherein a transmission characteristic fromone terminal portion to the other terminal portion on a high frequencyline connecting the two high frequency packages has the property ofcyclically varying in relation to frequency, and the frequency ofsignals transmitted along the high frequency line corresponds to that ata part of the cyclic variation curve of the transmission characteristicwhere transmittance is large.
 6. The wiring board according to claim 5,which satisfies: f ₁+{(f₂ −f ₁)/4}≦f ₀ ≦f ₂−{(f ₂ −f ₁)/4}  [Formula 1]where f₀ represents the frequency of signals transmitted along the highfrequency line, f₁ represents the frequency on the cyclic variationcurve of the transmission characteristic at a part on the lowerfrequency side adjacent to f₀, where transmittance is small, and f₂represents the frequency on the curve at a part on the higher frequencyside adjacent to f₀, where transmittance is small.
 7. The wiring boardaccording to claim 5, wherein the length of the high frequency line fromone terminal portion to the other terminal portion is (2n+1)λ/4 (n: anintegral number, λ: wavelength of signal frequency)
 8. The wiring boardaccording to claim 5, wherein one of the two high frequency packagesserves as a switching device.
 9. A high frequency module comprising oneor plurality of high frequency packages mounted on a wiring board, eachof the high frequency packages comprising: a dielectric substrateprovided with an input terminal and an output terminal; a high frequencyelement mounted on the surface of the dielectric substrate; and a highfrequency line formed on the dielectric substrate for connecting thehigh frequency element with the input terminal and with the outputterminal, wherein a transmission characteristic from the input terminalto the output terminal has the property of cyclically varying inrelation to frequency, and the frequency of signals transmitted alongthe high frequency line corresponds to that at a part of the cyclicvariation curve of the transmission characteristic where transmittanceis large.
 10. A high frequency module comprising at least two highfrequency packages and a wiring board, the high frequency packageshaving input terminals and output terminals being connected to a highfrequency line on the wiring board, wherein a transmissioncharacteristic from one terminal portion to the other terminal portionon the high frequency line connecting the two high frequency packageshas the property of cyclically varying in relation to frequency, and thefrequency of signals transmitted along the high frequency linecorresponds to that at a part of the cyclic variation curve of thetransmission characteristic where transmittance is large.
 11. A highfrequency module comprising at least two high frequency packages and awiring board, the high frequency packages having input terminals andoutput terminals being connected to a high frequency line on the wiringboard, each of the high frequency packages comprising: a dielectricsubstrate provided with an input terminal and an output terminal; a highfrequency element mounted on the surface of the dielectric substrate;and a high frequency line formed on the dielectric substrate forconnecting the high frequency element with the input terminal and withthe output terminal, wherein a transmission characteristic from theinput terminal to the output terminal has the property of cyclicallyvarying in relation to frequency, and the frequency of signalstransmitted along the high frequency line corresponds to that at a partof the cyclic variation curve of the transmission characteristic wheretransmittance is large, and a transmission characteristic from oneterminal portion to the other terminal portion on the high frequencyline connecting the two high frequency packages on the wiring board hasthe property of cyclically varying in relation to frequency, and thefrequency of signals transmitted along the high frequency linecorresponds to that at a part of the cyclic variation curve of thetransmission characteristic where transmittance is large.